The present invention relates to stranded cables, and more particularly, to stranded twisted pair patch cables for high-speed LAN applications.
Local area networks (LAN""s) now connect a vast number of personal computers, workstations, printers, and file servers in the modern office. A LAN system is typically implemented by physically connecting all of these devices with copper-conductor twisted-wire pair (xe2x80x9ctwisted-pairxe2x80x9d) LAN cables, the most common being an unshielded twisted-pair type (xe2x80x9cUTPxe2x80x9d) LAN cable. A conventional UTP LAN cable includes four twisted pairs, i.e. 8-wires. Each of the four twisted-pairs function as a transmission line to convey a data signal through the LAN cable. Each end of the LAN cable usually terminates in a modular-type connector with pin assignments of type xe2x80x9cRJ-45xe2x80x9d, according to the international standard IEC 603-7. Modular RJ-45 connectors may be in the form of either plugs or jacks, and a mated plug and jack is considered a connection.
In a typical installation, UTP LAN cables are routed through walls, floors, and ceilings of a building. LAN cable systems require constant care, including maintenance, upgrading and troubleshooting. In particular, LAN cables and connectors are subject to breakage or unintentional disconnection. Moreover, because offices and equipment must be moved, or because new equipment may be added to an existing LAN, the UTP cable is often manipulated and adjusted. In order to minimize disruption of a LAN system, two types of wiring are used. The first type of wiring is relatively stiff, and is installed in a substantially permanent or fixed configuration. The stiff wiring is used for horizontal connections through walls, or between floors and work areas. For the second type of wiring, a relatively short length of LAN cable, called a patch cord, is used. The patch cord includes a connector mounted on each end, and is used to interconnect between the fixed wiring of a building and the movable equipment at each end of the LAN cable system. Patch cords are typically manufactured and sold in predetermined lengths, for example two meters, with the modular RJ-45 plugs installed on either of the flexible cable.
Patch cords are an essential element of a LAN system, typically connecting moveable LAN-based equipment to a fixed module. Thus, when equipment is installed, patch cords are used to provide the final interconnection between the equipment and the rest of the LAN. To facilitate easy interconnection between the fixed wiring associated with a fixed module and the movable LAN-based equipment, the patch cord is relatively flexible. Specifically, the individual wires of a patch cord are typically formed from stranded metal conductor wires, which are more flexible than solid core wires.
Patch cords significantly impact the overall transmission quality of the LAN. Even though the cable and plugs that make up the patch cord are themselves compliant with appropriate standards, the assembled patch cord, when used as part of a user channel, may cause the user channel configuration to be out of compliance with accepted standards. Moreover, patch cords are often subject to physical abuse in user work areas as the patch cord is moved or manipulated by either the installer or the system user. As the patch cord is moved or manipulated, the strands within a wire may separate slightly, affecting the electrical properties of the wire. In particular, separation of the strands may result in greater attenuation of a data signal and impedance variations along the length of the patch cord.
To limit separation of individual strands within a wire during use, it is known to apply a tin solution to the surface of stranded copper wires to seal or bond the individual strands to adjoining strands of copper. However, tin is a poor conductor, and may adversely affect the electrical properties of the wire, and construction of tinned copper conductors requires an extra and difficult manufacturing step.
The present invention is directed to a method of forming flexible communications wire for use in Local Area Networks (LAN""s). The inventive method comprises forming a metal conductor from a plurality of individual metal strands, and subjecting the metal conductor to both compression and heat to slightly adhere the strands together.
Wires formed according to the present invention are sturdier than conventional stranded conductor wires, while retaining significant flexibility. In fact, a wire formed from according to the inventive method retains more flexibility than a wire having tin bonds between individual strands. In addition, because the strands are compressed, the wire outer diameter is reduced, which also reduces attenuation effects along the length of the wire. Significantly, the compression and heating steps may be applied simultaneously, decreasing manufacturing time and complexity.